Interlocking building blocks used in the construction of mortarless walls typically have projections on an upper surface of the block and have corresponding recesses on a lower surface of the block, the projections of one block being adapted to be received in, and interlock with, the recesses of an overlying block, thereby obviating the need for any securing mortar between courses. Such blocks may be used to construct building structures and are also used with increasing popularity in developing countries to reduce the building costs by decreasing the time required to complete a structure. Walls made from interlocking blocks are also gaining acceptance in zones having seismic activity.
Commonly, vertically adjacent blocks are staggered by one-half the length of a block to construct a wall or other architectural structure. Conveniently, the blocks used in masonry have a length to width ratio of 2:1 so that, when a first block is disposed transversely to a second block, such as at a corner, the first block occupies only half the length of the second block and the modular relationship between overlying blocks is not altered, thereby maintaining a uniform and aesthetic appearance. This relationship between the length and width is particularly important in interlocking blocks where the projections and recesses are in predefined positions on the blocks and there is no flexibility for adjusting the relative position of superimposed blocks.
In some circumstances, it is desirable to construct walls where the modular length of one block is maintained, but in which the thickness of the wall is varied. One might, for example, construct exterior walls of a structure which are relatively thicker than interior walls. While the length of the blocks used to construct a thick wall could be increased to be commensurate with an increased block width and to maintain the length-to-width ratio of 2:1, this is often not a practical solution. Such blocks are generally too bulky for handling and architects and masons become accustomed to making calculations based on a standard modular length unit. Typically, a modular length unit for a block is 400 mm and the associated width is 200 mm.
One problem which is addressed by this invention is to provide an interlocking building block in which a modular relationship can be maintained with blocks of varying widths, thus giving the builder more flexibility to construct a variety of architectural features, including walls which intersect to form partitions and corners.
The invention also has advantageous features for interlocking blocks disposed side-by-side in a course and for accommodating reinforcement bars traversing the length of a block and which link the blocks of a course together to strengthen the structure, as will be described in more detail below.